The ZeroAcess Botnet is epidemic. The Zeus keylogger banking malware is a persistent problem. And – in the sole sliver of good news – cybercriminals still do not have a handle on how to exploit mobile phones.

Call those the top three takeaways from the Q3 Kindsight Security Labs malware report.

Chilling news: 13% of home networks are infected with malware. Around half of those cases are what Kindsight classes as serious malware such as Zeus.

The single most virulent infection today is the ZeroAcess botnet, elaborated Kindsight security architect Kevin McNamee in an interview.

What ZeroAcess, which Kindsight estimates accounts for 17% of infected computers, does is generate clicks on pay per click advertisements on websites that are in some way part of the scam.

Infected machines, without direction from their owners, visit the target sites and click, to a tune Kindsight estimated adds up to $900,000 in stolen money daily.

Particularly worrisome, said McNamee, is that the incidence of ZeroAcess has been spreading fast. The malware spreads via spam email that prompts the recipient to click on a link – perhaps masquerading as a tax agency but in reality it is a front door for the criminal enterprise. At the site the malware is installed and the infected computer then falls under the control of a criminal enterprise.

Zeus, the banking trojan, has achieved a steady rate of infection, said McNamee. Kindsight said it now accounts for 2.4% of infected machines.

The only bright spot is that, so far, cybercriminals appear stymied about how to exploit mobile phones in general and Android phones in particular, conceded McNamee.

Android is thought to be a higher priority target because the Apple App Store is believed to have more rigorous security checking before it releases apps.

Even so, said McNamee, most of what KIndsight is finding in Android traffic “is nuisance software. It’s not very effective.”

That, he suggested will not always be the case, but, right now, mobile users are largely safe from genuinely sophisticated and potent criminal malware.

Majority owned by networking company Alcatel-Lucent, Kindsight is headquartered in Mountain View, Calif.